Well seems the AR's started in the 1:24 twist rate, but more options are becoming available. I see the bolt guns running 1:16 twist. Figured Id start a thread with what Im finding is available, so others joining the game will have some options. Ill try to update as I go.Mcgowen will do 1:10 thru 1:24 http://mcgowenbarrel.com/chrome-moly-barrels/